When its value HIGH, it ignores the master. When a device’s Slave Select pin value is LOW, it can communicate with the master.
This line is used for sending data to the peripherals. This data line in the MISO pin is used to receive the data from the Slave.
These are the clock pulses, that are used to synchronize the transfer of data. It is used by the microcontrollers to communicate with one or more peripheral devices quickly. SPI stands for Serial Peripheral Interface. SPI pins on the board: D13(SCK), D12(MISO), D11(MOSI)